1. Field of the invention
The present invention relates to a liquid crystal display, and more particularly to a method for asymmetrically aligning polarizer and rubbing axes in order to remove a ghost image and a rubbing mura caused by an electric field applied to a panel under a low gray scale and dark state of a fringe field switching liquid crystal display.
2. Description of the Prior Art
FIG. 1 is a view showing a conventional fringe field switching liquid crystal display (FFS-LCD). FIG. 2 is a view showing a polarizer axis of the FFS-LCD shown in FIG. 1.
As shown in FIG. 1, in a conventional ultra-FFS, a second ITO electrode 104 overlaid on a first ITO electrode 102 is fabricated as an electrode having an oblique-comb shape, and a liquid crystal is aligned at an angle of 0°. Accordingly, the liquid crystal caused by an electric field is twisted in such a manner that upper and lower sides of the liquid crystal are directed opposite to each other, thereby preventing the chromatic shift of yellow color or blue color caused by dielectric anisotropy.
According to the conventional FFS-LCD having the above construction, since an overlapped region between electrodes is very wide, layers such as insulation layers may be deteriorated if the conventional FFS-LCD operates for a long period of time, causing inferior ghost images. In order to correct such a disadvantage, various shapes and structures of electrodes have been studied and proposed.
In a normally black mode of a conventional FFS, an L0 (dark and black) state is maintained when a voltage is not applied to the conventional FFS and a L255 gray scale (white) is realized because a liquid crystal is aligned in an electric field direction or a vertical direction according to an applied electric field.
Factors such as impurity within liquid crystal, an insulating layer between electrodes, and a liquid crystal-alignment layer degraded due to an electric field applied for a long time through the above-described operating principle, deteriorates quality of an image due to a ghost image and a mura in a low gray scale state.